Remove calls to MessageLoop::current() in sync.

sync/internal_api/public/engine/model_safe_worker.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SYNC_INTERNAL_API_PUBLIC_ENGINE_MODEL_SAFE_WORKER_H_
 #define SYNC_INTERNAL_API_PUBLIC_ENGINE_MODEL_SAFE_WORKER_H_
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/message_loop/message_loop.h"
+#include "base/single_thread_task_runner.h"
 #include "base/synchronization/lock.h"
 #include "base/synchronization/waitable_event.h"
 #include "sync/base/sync_export.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/internal_api/public/util/syncer_error.h"
 
 namespace base {
 class DictionaryValue;
 }  // namespace base
 
@@ skipping 102 matching lines @@
 
   // Signal set when work on native thread is finished or when native thread
   // is to be destroyed so no more work can be done.
   base::WaitableEvent work_done_or_stopped_;
 
   // Notified when working thread of the worker is to be destroyed.
   WorkerLoopDestructionObserver* observer_;
 
   // Remember working loop for posting task to unregister destruction
   // observation from sync thread when shutting down sync.
-  base::Lock working_loop_lock_;
-  base::MessageLoop* working_loop_;
+  base::Lock working_task_runner_lock_;
+  scoped_refptr<base::SingleThreadTaskRunner> working_task_runner_;
 
   // Callback passed with UnregisterForLoopDestruction. Normally this
-  // remains unset/unused and is stored only if |working_loop_| isn't
+  // remains unset/unused and is stored only if |working_task_runner_| isn't
   // initialized by the time UnregisterForLoopDestruction is called.
   // It is safe to copy and thread safe.
   // See comments in model_safe_worker.cc for more details.
   base::Callback<void(ModelSafeGroup)> unregister_done_callback_;
 };
 
 // A map that details which ModelSafeGroup each ModelType
 // belongs to.  Routing info can change in response to the user enabling /
 // disabling sync for certain types, as well as model association completions.
 typedef std::map<ModelType, ModelSafeGroup> ModelSafeRoutingInfo;
 
 // Caller takes ownership of return value.
 SYNC_EXPORT std::unique_ptr<base::DictionaryValue> ModelSafeRoutingInfoToValue(
     const ModelSafeRoutingInfo& routing_info);
 
 SYNC_EXPORT std::string ModelSafeRoutingInfoToString(
     const ModelSafeRoutingInfo& routing_info);
 
 SYNC_EXPORT ModelTypeSet GetRoutingInfoTypes(
     const ModelSafeRoutingInfo& routing_info);
 
 SYNC_EXPORT ModelSafeGroup GetGroupForModelType(
     const ModelType type,
     const ModelSafeRoutingInfo& routes);
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_ENGINE_MODEL_SAFE_WORKER_H_